Belt-driven door operator with slackcontrolled safety switch



HHHHU L. G. TATRO SAFETY SWITCH ATTORNEY Aug. 20, 1957 BELT-DRIVEN DOOROPERATOR WITH SLACK-CONTROLLED Filed June 13, 1956 m/w/ A 2 mm w m m w 33 KW m .QQMQW A. m mm Q, w. in Wm WM w NM N v EM. \QN RN\ ww RM 0 Wm HWM 3 L. G. TATRO 2,803,454 BELT-DRIVEN DOOR OPERATOR WITHSLACK-CONTROLLED SAFETY SWITCH Aug. 20, 1957 V s Sheets-Sheet 2 FiledJune 15, 1956 IN VEN TOR. 1 192; a 72720 L. G. TATRO 2,803,454BELT-DRIVEN DOOR OPERATOR WITH SLACK-CONTROLLED SAFETY SWITCH Aug. 20,1957 3 Sheets-Sheet 3 Filed June 13, 1956 INVENTOR. 734720 ATTUENEYUnited States Patent r 2,803,454 Patented A g- 1957 BELT-DRIVEN DOOR()PERATOR WITH SLACK- CONTROLLED SAFETY SWITCH Lysle G. ,Tatro, Reseda,Califi, assignor to Pres-To-Line Corp. of America, Los Angeles, Calif acorporation ,of California Application June 13, 1956, Serial No. 591,034

12 Claims. (Cl. 268-59) is to provide a door-operating mechanism thatautomatically stops its closing or descending movement upon encounteringany object in the path of such movement.

Another object of the invention is to provide a dooroperating mechanismthat may be remotely controlled,

and which applies the full power of its prime mover for moving a door toopen or raised position, which applies said power in a manner tending toprovide a slippage or clutch type of drive for moving a door to loweredor closed position, and which, during the latter movement and uponencountering an obstruction, becomes fully disconnected to stop descentof the door.

A further object of the invention is to provide a mechanism of thecharacter referred to in which the prime mover is stopped upon arrestingof closing movement of the door.

The invention also has for its object to provide such means that arepositive in operation, convenient in use, easily installed in a workingposition and easily disconnected therefrom, economical of manufacture,relatively simple, and of general superiority and serviceability.

The invention also comprises novel details of construction and novelcombinations and arrangements of parts,

' which will more fully appear in the course of the followingdescription. However, the drawings merely show and the followingdescription merely describes, preferred embodiments of the presentinvention, which are given by way of illustration or example only.

In the drawings, like reference characters designate similar parts inthe several views.

Fig. 1 is a top plan view of a door-operating mechanism according to thepresent invention.

Fig. 2 is a side elevational view thereof in operative position.

Fig. 3 is an enlarged longitudinal sectional view as taken on line 33 ofFig. 1.

Fig. 4 is a cross-sectional view as taken on line 44 of Fig. 3.

Fig. 5 is a plan sectional view as taken on line 5-5 of Fig. 2 with themechanism in the position assumed when the door is lowered.

Figs. 6 and 7 are cross-sectional views as taken on the respective lines66 and 77 of Fig. 5.

Fig. 8 is an enlarged longitudinal sectional view as taken on line 88 ofFig. 1.

Fig. 9 is a view similar to Fig. 2, showing a modification of theinvention.

Fig. 10 is an enlarged and fragmentary plan view of the left-hand end ofFig. 9.

Fig, 11 is a partial side elevational and partial longistitute part ofthis invention.

tudinal sectional view of the portion of the mechanism shown in Fig. 10.

The present mechanism is shown as installed in operative position on aceiling 10 in transverse relationship to the width of a door opening 11in a wall '12. Said opening 11 is shown as provided with an overheaddoor 13, the guides and other hardware which guide the movement ofsaid-door between closed and open position'being omitted since the sameare generally well-known and do not con- This above merely discloses atypical environment in which the present mechanism may be installed.

The door-operating mechanism that is illustrated comprises, generally, aprime mover 15, an operating unit 16 connected to and embodying acontrol for said prime mover, an elongated frame 17 extending from theunit '16 and constituting a combined guideway and slideway, a carriage18 guided in the frame and connected 'to the door 13, a drive means 19connected to the prime mover and to the carriage to move the latterlongitudinally along the frame, limit means '20 to control the limit ofmovement of the carriage according to the limit of movement of the door13 between open and closed positions, a tension-mounted slide means 21controlling the operation of the drive means 19, and means 22 operableby said drive means, as controlled by the slide means 21, to stop theprime mover when there is an obstruction in the path of door 13, whendescending.

The prime mover 15 preferably comprises a reversing motor which may beset into operation in various ways, by a manual switch, byradio-controlled means, by a photo cell circuit, etc. The particularmode of operation is not here important and may be varied as desired. Inthis instance, the prime mover is provided with a worm 23 on the outputshaft 24 thereof.

The operating unit 16 may comprise an enclosure in which worm 23 residesand, also, may house such electrical components that may be required foroperating the reversing motor according to the mode or type of controlor operation. As shown, said unit 16 houses a shaft 25 that is inoperative engagement with the prime mover through a worm wheel 26 thatis in mesh with worm 23. Thus, the speed of the shaft 25 is relativelyslower than the speed of the motor and is self-locked against rotationexcept by the motor.

The frame 17 is shown in the form of the invention illustrated in Figs.1 to 8 as comprising a pair of elongated angles 27 in transverselyspaced relation so that their corner edges 28 are opposite and paralleland their Walls 29 define slideways. Said angles 27 are connected bytransverse straps 30 that are longitudinally spaced to render the framerigid. At the end directed toward the unit 16, the frame angles areformed to have spaced ears 31 through which shaft 25 extends and inwhich the same has bearing. Since the motor 15 is provided with a pad 32for fastening to a ceiling 1-3 and the opposite end of the frame maycarry members, such as the angles 53 for fastening either to the ceilingor to wall 12, the opposite ends of the frame are rigidly secured inoperative position.

The carriage 18 comprises a pair of vertically spaced plates 34 and 35that are connected at their corners by studs 36 on which are mountedwheels 37 disposed between said plates. Said wheels have traction in thementioned corner edges of the angles 27, the plates 34 and 35, thereby,residing in the space between the angles. Said carriage is provided witha depending and rigid arm 38 that extends from a cam member 39 which issecured to the lower plate 35. The latter member is shown as arectangular block of which one edge 40 constitutes the cam part, thesame terminating at rounded corners 41, as shown in Fig. 5.

and a resilient mount 50 for said slide.

drive shaft 25 and is shown as comprising a grooved pulley 44 affixed tosaid shaft and disposed between the ears 31, an endless belt 45 trainedover said pulley and over a similar idler pulley 46 carried by the slidemeans 21 later described in detail. The belt 45 is preferably made ofrubber or like material and has frictional engagement in the grooves ofthe pulleys over which trained to provide a substantially non-slippingdrive connection between pulley 44 and the belt.

The limit means 20 of Figs. 1 to 8 is shown as two longitudinally spacednormally-closed switches 47 and 48 that are attached to one of theangles 27 and are so placed and spaced from each other as to be actuatedby the cam face 40 at the ends of the movement of the door to open andclosed position. Said switches are connected in the electric circuit ofthe prime mover 15 so that the latter will operate in one direction orthe other depending on which switch is held open by the carriage whilethe other maintains its closed position. In any case, switch 47, whenopened by face 40, stops the prime mover after moving the door to openposition. Then, after the current to the motor 15 is instituted, asexplained before and the door starts down to closed position, opening ofswitch 48 stops said motor. Door opening is instituted in the same wayexcept switch 47 is closed and the motor direction is reversed.

The slide means 21 is best seen in Figs. and 7 and comprises a slide 49,guided in the slideway formed by frame members 27, and mounting theidler pulley 46, Said mount is shown as a cross bar 51 on the slide 49,a set of elastic members in the form of springs 52 connected at one endto said bar 51 and at the other end to a plate 53, a connecting link,shown as a turnbuckle 54, connected at one end to said plate 53, and afixed bridge member 55 connected to the other end of said turnbuckle.

Said bridge 55 is preferably placed near the end of frame 17 with theslide 21 directed toward the end of the frame to which the prime moveris connected. Thus, the belt 45 is subject to the tension imposedthereon by the springs 52 and according to the adjusted length of theturnbuckle 54. 7

The means 22 is shown as a switch 56, mounted by a bracket plate 57, onone frame member 27, and provided with an actuator 58 in contact withbelt 45 rearward of the bight 59 that said belt forms over pulley 44.Said switch 56 is normally closed to maintain the circuit to the primemover and when open, breaks said circuit.

In the modification shown in Figs. 9 and 10, the frame 17a, rather thanbeing formed of strap-connected angle members, is integrally formed toprovide carriageand slide-guiding means of comparable cross-sectionalform to that of the earlier-described form of the invention.

The drive means 19 of the modification has an endless belt 45a that, inpart, comprises a rubber or like material section 70 that is trainedover and has driving connection with the pulley 44 and, in part, a cablesection 71 that is trained over pulley 46 of the slide means 21. Thearrangement is such that section 70 does not achieve engagement withpulley 46 and section 71 does not achieve engagement with pulley 44.However, the endless belt 45a has the same functional properties as belt45 and of rubber belt.

The limit means of the alternative or modified form of the inventionomits the switches 47 and 48 and makes use of the switch 56 to stop themotor at each end of movement of the door 13. By providing the beltsection with projections or cams 72 and 73-one adjacent one end of saidsection and the other adjacent the other end the switch actuator 58 ismoved by said projections to trip switch 56. It will be clear that whenthe door 13 reaches full open position, projection 73 acts to stop thedrive, as above, and when the door reaches full closed position,projection 72 stops the drive. The opening of switch 56 to stop thedrive when there is an obstruction in the path of descent of the door iscarried out as stated in the second paragraph below. Thus, the use ofprojections 72 and 73 enables use of but one control switch ,with theresultant economy that follows elimination of ,the limit switches andthe wiring necessary therefor.

The normal operation of the present door operator is deemed to be. clearfrom the foregoing. Any overrun of the door-closing drive is arrested bythe door achieving its fully-closed position against the pavement in thedoor opening. Overrun of the door-opening drive is arrested 'by a stopblock 60 on the belt 45 and achieving engage- .ment with cross strap 61of the frame 17.

It will be noted that block 39 is grooved at 62 for the belt 45 and thepart of said belt that is in the groove is fastened by bolts 63 toeffect a firm and non-slipping connection between said belt and thecarriage 18. Since the gears 23 and 26 are self-locking, there is nopossibility of the door to descend except when under power of the primemover.

If during the closing movement of the door, the same encounters anobstruction, the movement of link 42 will be arrested since the same isconnected to the door. Thus, as belt 45 seeks to continue its drivemovement and said link stops movement of the arm 38, the latter willtilt and cause the springs 52 to stretch, producing slack in the belt45. This stretching of the spring and formation of the slack resultsfrom the positive drive between pulley 44 and the belt pulling on thetop run 64 of the belt while movement of the carriage 18 is arrested.Since the top run 64 is held taut by said positive drive and thecenter-to-center distance of the pulleys 44 and 46 foreshortensaccording to the stretch of springs 52, the slack in the belt forms inthe lower run 65. Inasmuch as said slack is first formed where the run65 starts at pulley 44, the switch actuator 58 is depressed thereby tocause opening of switch 56 immediately that the normal descendingmovement is arrested.

While the foregoing has illustrated and described what is nowcontemplated to be the best mode of carrying out the invention, theconstruction is, of course, subject to modification without departingfrom the spirit and scope of the invention. It is, therefore, notdesired to restrict the invention to the particular form of constructionillustrated and described, but to cover all modifications that may fallwithin the scope of the appended claims.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

1. A door-operating mechanism comprising an elongated frame, an endlessbelt mounted in said frame, a reversing drive for said belt, a resilientbelt tensioner, a connection between the belt and a door to move thedoor between open and closed positions according to the direction of thereversing drive, means responsive to an obstruction in the path ofclosing movement of the door to stretch the belt tensioner to introduceslack in the belt, and means engaged with said slack to stop thedoorclosing drive.

2. A door-operating mechanism comprising an elongated frame, an endlessbelt mounted in said .frame,'a reversing drive for said belt, aresilient belt tensioner, a connection between the belt and a door tomove the door between open and closed positions according to thedirection of the reversing drive, limit switches carried by the frame inlongitudinally spaced relation to stop said drive at opposite end pointsof its movement, means responsive to an obstruction in the path ofclosing movement of the door to stretch the belt tensioner to introduceslack in the belt, and means engaged with said slack to stop thedoor-closing drive.

3. A door-operating mechanism comprising an elongated frame, an endlessbelt mounted in said frame, a reversing drive for said belt, a resilientbelt tensioner, a connection between the belt and a door to move thedoor between open and closed positions according to the direction of thereversing drive, said connection including a carriage afiixed to thebelt and guided in the frame, and a link interconnecting said carriageand the door, means responsive to an obstruction in the path of closingmove ment of the door to stretch the belt tensioner to introduce slackin the belt, and means engaged with said slack to stop the door-closingdrive.

4. A door-operating mechanism comprising an elongated frame, an endlessbelt mounted in said frame, a reversing drive for said belt, a resilientbelt tensioner, a connection between the belt and a door to move thedoor between open and closed positions according to the direction of thereversing drive, the drive including a reversing electric motor as aprime mover, a controller for said motor in feeling engagement with thebelt to respond to a slackening of the belt and to open the circuit tothe motor, and means actuated by an obstruction in the path of closingmovement of the door to cause said slackening of the belt.

5. A door-operating mechanism according to claim 4 in which thelast-mentioned means comprises a springtensioned slide guided forlongitudinal movement in the frame, the same being tensioned in adirection to tauten the belt.

6. In a door-operating mechanism, an endless belt trained over twolongitudinally spaced pulleys, a reversing drive connected to one ofsaid pulleys, a resilient belt tautener mounting the other pulley, acarriage connected to said belt and adapted to be connected to a door toopen and close the same according to the direction of movement of thereversing drive, means responsive to an obstruction in the path ofclosing movement of the door to stretch said belt tautener while thebelt is being driven in a directon to close the door to introduce slackin the belt, and means operable by said slack to control the mentioneddrive to arrest closing movement of the belt and door.

7. In a door-operating mechanism according to claim 6, the pulleyconnected to the drive being grooved, and the belt having frictionalengagement in the groove of the pulley to constitute a non-slippingconnection during drive in the door-opening direction and to constitutea slipping connection upon introduction of slack in the belt.

8. In a door-operating mechanism according to claim 6, the mentionedreversing drive being self-locking, the pulley connected to the drivebeing grooved, and the belt having frictional engagement in the grooveof the pulley to constitute a non-slipping connection during drive inthe dooropening direction and to constitute a slipping connection uponintroduction of slack in the belt.

9. a door-operating mechanism, an endless belt trained over twolongitudinaliy spaced pulleys, a reversing drive connected to one ofsaid pulleys, a resilient belt tautener mounting the other pulley, acarriage connected to said beit and adapted to be connected to a door toopen and close the same according to the direction of movement of thereversing drive, limit means controlled by said carriage at oppositeends of its movement to stop the drive, means responsive to anobstruction in the path of closing movement of the door to stretch saidbelt tautener while the belt is being driven in a direction to close thedoor to introduce slack in the belt, and means operable by said slack tocontrol the mentioned drive to arrest closing movement of the belt anddoor.

10. A door-operating mechanism comprising an elongated frame, an endlessbeit mounted in said frame and provided with longitudinally spacedswitch actuating elements, a reversing drive for said belt, a resilientbelt tensioner, a connection between the belt and a door to move thedoor between open and closed positions according to the direction of thereversing drive, a switch controlling said drive and carried by theframe and provided with an actuator in feeling engagement with theendless belt, said actuator being moved by said actuating elements toswitch-opening position to stop said drive, and means responsive to anobstruction in the path of closing movement of the door to stretch thebelt tensioner to introduce slack in the belt where said switch actuatorengages the belt, the latter means including the drive-controllingswitch.

ll. A door-operating mechanism according to claim 4 and in whichlongitudinally spaced portions of the belt are provided withcontroiler-operating projections to stop the prime mover when the doorhas reached either its open or its closed position.

12. In a door-operating mechanism, an endless belt trained over twolongitudinally spaced pulleys, a reversing drive connected to one ofsaid pulleys, a resilient belt tautener mounting the other pulley, acarriage connected to said belt and adapted to be connected to a door toopen and close the same according to the direction of movement of thereversing drive, limit means controlled by said endless belt at oppositeends of its movement to stop the drive, means responsive to anobstruction in the path of closing movement of the door to stretch saidbelt tautener while the belt is being driven in a direction to close thedoor to introduce slack in the belt, and means operable by said slack tocontrol the mentioned drive to arrest closing movement of the belt anddoor.

References Cited in the file of this patent UNITED STATES PATENTS2,334,981 Ackley Nov. 23, 1943 2,335,336 Zoller Nov. 30, 1943 2,401,082Konter May 28, 1946 2,544,239 Schirmer Mar. 6, 1951

